1. Technical Field
The present disclosure relates to hand held surgical stapling apparatus. More particularly, the present disclosure relates to retraction mechanisms for use with hand held surgical stapling apparatus.
2. Background of Related Art
Surgical apparatus capable of fastening tissue layers are well known in the art. In general, surgical stapling apparatus include two elongated jaw members designed for capturing or clamping tissue. One jaw member typically contains a staple cartridge housing a plurality of staples. Conventional staple cartridges include at least two lateral rows of retention slots. These retention slots are adapted to receive staples. The other jaw member has an anvil that defines a surface for forming the staple legs as the staples are driven from the staple cartridge. The stapling operation is usually effected by cam members that translate through the staple cartridge. The cam members act on staple pushers to eject the staples from the staple cartridge. A knife may move axially between the rows of retention slots to cut or open the stapled tissue.
Another surgical stapling apparatus applies a double row of staples on each side of the incision. This surgical stapling apparatus has a disposable loading unit wherein a cam member moves through an elongate guide path between two sets of staggered staple carrying grooves. Staple drive members are located within the grooves and are positioned in such a manner so as to be contacted by the longitudinally moving cam member. The staple members eject the staples in the staple cartridge as the cam member moves axially along the elongate guide path.
Each of the apparatus described hereinabove is designed for use in conventional surgical procedures wherein surgeons have direct manual access to the operative site. In endoscopic or laparoscopic procedures, however, surgery is performed through a small incision or through a narrow cannula inserted through small entrance wound in the skin. Endoscopic surgical stapling devices have been developed to address the specific needs of endoscopic and laparoscopic surgical procedures. A few examples of endoscopic surgical stapling devices are disclosed in U.S. Pat. Nos. 5,312,023; 5,326,013; and 6,241,139, the entire contents of each of which are incorporated herein by reference.
Some of the instruments described in the patents listed above have retraction mechanisms to return the firing drive of the instrument to a retracted or proximal position. These retraction mechanisms include a pair of refractor knobs movably positioned along a barrel portion of a handle assembly. The retraction knobs can be manually pulled proximally to retract the firing drive to its original position after firing the instrument.
Other endoscopic stapling instruments include powered retraction mechanisms. For instance, U.S. Patent Application Publication No. 2008/0245842, filed Apr. 9, 2007, the entire contents of which is hereby incorporated by reference, discloses a surgical stapling apparatus including a powered retraction mechanism. An embodiment of this retraction mechanism includes a motor operatively associated with a pulley and a slip clutch. The pulley is configured to retract the firing drive of the surgical stapling apparatus once the slip clutch moves to its engaged position.
The surgical apparatus described above have provided significant clinical benefits. Nonetheless, improvements to these instruments are possible. For instance, it would be beneficial to provide a surgical stapling apparatus with a clutch-less powered retraction mechanism to reduce the weight and size of the mechanism. By minimizing the number of parts, the retraction mechanism could be easily placed within a handle assembly of a surgical stapling apparatus.